Designation:C1368−18StandardTestMethodforDeterminationofSlowCrackGrowthParametersofAdvancedCeramicsbyConstantStressRateStrengthTestingatAmbientTemperature1ThisstandardisissuedunderthefixeddesignationC1368;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthedeterminationofslowcrackgrowth(SCG)parametersofadvancedceramicsbyusingconstantstressraterectangularbeamflexuraltesting,ring-on-ringbiaxialdiskflexuraltesting,ordirecttensilestrength,inwhichstrengthisdeterminedasafunctionofappliedstressrateinagivenenvironmentatambienttemperature.Thestrengthdegradationexhibitedwithdecreasingappliedstressrateinaspecifiedenvironmentisthebasisofthistestmethodwhichenablestheevaluationofslowcrackgrowthparametersofamaterial.NOTE1—Thistestmethodisfrequentlyreferredtoas“dynamicfatigue”testing(1-3)2inwhichtheterm“fatigue”isusedinterchangeablywiththeterm“slowcrackgrowth.”Toavoidpossibleconfusionwiththe“fatigue”phenomenonofamaterialwhichoccursexclusivelyundercyclicloading,asdefinedinTerminologyE1823,thistestmethodusestheterm“constantstressratetesting”ratherthan“dynamicfatigue”testing.NOTE2—Inglassandceramicstechnology,statictestsofconsiderabledurationarecalled“staticfatigue”tests,atypeoftestdesignatedasstressrupture(SeeTerminologyE1823).1.2ValuesexpressedinthistestmethodareinaccordancewiththeInternationalSystemofUnits(SI)andIEEE/ASTMSI10.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.1.4Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheD...
